Power over ethernet to USB adapter

ABSTRACT

A power adapter comprising a POE connector for receiving electrical power from the power lines of a POE cable, a transformer circuit and a USB connector for delivering electrical power to a USB powered device, wherein a POE cable provides power to the USB powered device. The power adapter can have a POE receptacle for receiving an Ethernet plug, to receive the POE power, and a USB receptacle to receive a USB plug from a USB powered device, or dedicated wires from one or more of the POE power supply and/or the USB powered device. 
     Also, a method for providing USB power comprising the steps of running a POE cable from a power source to an adapter, adapting the POE power from the POE cable to USB power and making the USB power available to one or more USB powered devices.

FIELD OF THE INVENTION

The present invention relates to electrical powered systems, standardsand devices. More particularly, the present invention relates to devicesand methods for adapting power from Power Over Ethernet (POE) lines touniversal serial bus (USB) power.

BACKGROUND OF THE INVENTION

USB standard technology was developed as a bus for connection betweencomputers and electronic devices. The USB connection was designed toprovide both communication and a power supply. Since its introduction,however, USB has evolved to replace a variety of computer interfaces,such as serial and parallel ports. USB has also evolved for use as aseparate power charger for portable devices. With respect to theelectrical power related to USB, the USB standard defines an electricalsignal of 5 volt DC, with a maximum voltage of 5 V (±5%).

Many consumer products including, for example, I-pads, cell phones,PDA's, etc. (“USB powered devices”), derive their operating/batteryrecharge power from the (nominal) 5 volt DC power available on acomputer USB port. AC wall mount charging adapters, which also utilizethe USB connector as the connection point for the power supply, havebecome popular to recharge these USB powered devices when a computer USBport is not available. Such adapters generally include an AC power plugand a USB port or wire to a USB or other universal connector, such as anApple dock connector. Of course, when referring to USB connectors, it isunderstood that there are many different types of USB connectors,including Type A, Type B, Mini-A, Mini-B, Micro-A, Micro-B, Apple dockconnectors, etc., all of which are intended to be covered herein.

There are also retail, commercial and other applications requiring thefixed or semi-permanent mounting of USB powered devices. For example,stores often provide tablets such as iPads for an employee to search,provide customer information and/or order from one or more fixedlocations in a retail establishment. In such applications, the USBpowered devices are typically powered from an AC power adapter,requiring that an AC receptacle be installed at each location at a costof several hundred dollars.

Similarly, USB “Charging Stations” are provided for convenience in manypublic areas, such as airports and conference facilities. These chargingstations are provided to allow charging of USB powered devices whentraveling. Such charging stations are also typically powered from an ACline which requires a receptacle and costly line power connection.

Power over Ethernet, or POE, technology describes a system for passingelectrical power safely along with data on Ethernet lines or cables.Power is supplied in common mode over one of two designated differentialpairs of wires in the Ethernet cables, originating from a power supplywithin a POE enabled network. The original IEEE 802.3af-2003 POEstandard provided up to 15.4 watts of DC power to each device, however,the updated IEEE 802.3 at-2009 POE standard provides up to 25.5 watts ofpower. The voltage range available with POE is from about 37 to about 57volts.

POE technology is considered especially useful for powering certaindevices which require more power than USB offers and when longer runs ofcable are required than USB permits. In this regard, Category 5 POEcable and power radios and other low power devices through over 100meters of cable, an order of magnitude farther than the theoreticalmaximum of USB.

Moreover, POE cable is considered to be easy to run and is readilyavailable in most commercial spaces. Due to the low DC voltage of POEcompared to standard AC power supply, the installation of a POE cabledrop does not require an electrician. Therefore, bringing low DC voltagePOE power to locations fairly remote from a power supply via POE cablehas been shown to be cost effective.

Notwithstanding the above, there is a need for providing USB power fromremote power supplies over relatively long distances, when consideringUSB power, in an efficient and cost effective manner.

SUMMARY OF THE INVENTION

It has been discovered that USB powered devices can be powered from aUSB connector, commonly a type A receptacle, which is powered by POEcable. In keeping, the present invention is directed to a power adaptercomprising a POE power line connector for receiving electrical powerfrom the power lines of a POE cable, a transformer circuit and a USBpower line connector for delivering electrical power to a USB powereddevice, wherein a POE power line provides power to the USB powereddevice.

In a preferred embodiment, the POE power line connector comprises anEthernet jack, or receptacle, which can receive a standard POE, orEthernet, plug. Notwithstanding, it is understood that the POE connectorcan comprise any type of electrical connection to the power adapter,such as spring contacts, screw down contacts, push-in contacts, strippedwires, etc., that establish an electrical connection between the POEcable power source and the power adapter. It is also understood that theonly lines of the POE cable that are necessary are the lines providingpower. Therefore, when referring to POE cable herein, it is onlyintended that such POE cable include the dedicated power lines of POEcable. Of course, absent the manufacture of POE cable with onlydedicated power lines, standard POE cable is well suited to practice theinvention.

Similarly, the USB power line connector in the preferred embodiment is aUSB type A receptacle for receiving a USB type A plug, however, can beany type of electrical connection to the USB powered device. Forexample, the USB power line connector may be a Type A, Type B, Mini-A,Mini-B, Micro-A, Micro-B, Apple dock connector or other plug that can beinserted directly into the USB powered device or other contacts, asdescribed above with respect to the POE connector. Additionally,depending on the power available from the POE cable, more than one USBconnector or line can be associated with a single POE line.

Between the POE power line connector and the USB power line connector isthe transformer circuit which converts the POE power, most commonly 48volt POE power under the current standard, to 5 V DC USB power. As setout above, more than one USB power line connector may be associated witha single POE power line if the POE power line has sufficient power.

Conversion of the POE power to USB power can be accomplished by anynumber of circuit designs. A preferred circuit would include inductorsto present the proper impedance to Ethernet data pairs while extractingthe POE DC voltage at center-tap connections. The POE DC voltageavailable at either the data or spare pairs of the network drop may thenbe rectified. Filtering and HF suppression of the raw DC is preferablyprovided and associated circuitry comprises the switching regulatorcircuitry that converts the POE DC voltage to an isolated, regulated 5 VDC supply. Isolated feedback for the regulator is preferably providedand associated components and circuitry would provide the physicalconnection to the USB bus while presenting the appropriate USB data linebiasing to support USB devices as well as a dedicated charging portmode.

The power adaptor of the present invention can take a variety of forms,all intended to be covered in this application. For example, the poweradapter can take the form of a self-contained encased device that can becarried by a user having a POE receptacle and a USB receptacle. A usercan then plug a POE cable extension with an Ethernet jack into the POEreceptacle and a USB powered device's charger cable into the USBreceptacle. Alternatively, the power adapter can have a POE power lineconnector in the form of an Ethernet jack or plug on a wire extendingfrom the power adaptor for the user to plug into an existing Ethernetreceptacle found in virtually every office. Similarly, the USB powerline connector can be in the form of a USB plug, taken from the varietyof USB plugs available, on the adapter or on a wire extending from thepower adapter, such that the power adapter can take the form of aportable adapter or a desktop dock.

The power adapter can also take the form of a component for permanentmounting in an AC electrical box using one or more mounting screws,clips or the like to fix the power adapter in the AC electrical box. Inthis embodiment, the power adapter preferably has the POE power lineconnector on an area that is only accessible from within the ACelectrical box and a USB receptacle on the portion accessible to userson the exterior of the AC electrical box. The invention furthercontemplates use of the AC electrical box mounted power adapter used incombination with or elements to mount a USB powered device such as atablet computer to the same AC electrical box, thereby eliminating allexposed wiring and providing a clean installation.

Also part of this invention is the method for providing USB power to aremote location comprising the steps of running a POE cable from a powersource to a remote power adapter, transforming the POE power from thePOE cable to USB power, and making the USB power available to a USBpowered device.

BRIEF DESCRIPTION OF THE DRAWINGS

The attached drawings are intended to better illustrate a preferredembodiment of the present invention without limiting the invention inany manner whatsoever.

FIG. 1 is a perspective view of a portable POE to USB power adapteraccording to the present invention.

FIG. 2 is an elevation of a POE to USB power adapter according to thepresent invention, mounted in a standard two-gang AC electrical box,with POE and USB cables connected.

FIG. 3 is an elevation of a prior art tablet computer mounting deviceused for mounting a tablet computer over an AC electrical box.

FIG. 4 is an elevation of a POE to USB power adapter mounted in an ACelectrical box behind a cover plate with the USB connector exposed.

FIG. 5 is a basic schematic of a preferred method of adapting POE powerto USB power for use in the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The following description of preferred embodiments is presented todescribe the present invention and is not to be construed to limit thescope of the appended claims in any manner whatsoever.

The present invention is shown in FIGS. 1 and 2 in the form of a poweradapter 2 comprising a POE power line connector 4 for receivingelectrical power from the power lines of a POE cable, a transformercircuit and a USB power line connector 6 for delivering electrical powerto a USB powered device (not shown), wherein power from a POE cable 8provides power to a USB powered device through a USB cable 10.

As shown in FIG. 1, the preferred power adapter 2 of the presentinvention can take the form of a portable device that can be carried bya user to power a USB powered device when away from a computer or ACoutlet. In this embodiment, the POE power line connector 2 is preferablya standard Ethernet connector into which a POE cable can be plugged. Auser could carry a short “jumper” cable to plug into an Ethernet jackfound on most office walls to provide USB power at the USB connector 6.Similarly, the user would be expected to carry a USB cable to connect aUSB powered device to the power adapter 2 in this embodiment.

Of course, the invention contemplates the POE connector 4 and/or USBconnector 6 being any suitable form to conduct the necessary POE and/orUSB power. Of these, the most preferred would be a POE cable hard wiredto the transformer circuit with an Ethernet jack or plug at the terminalend for plugging into an POE receptacle. Likewise, a USB cable could behardwired to the transformer circuit with a USB jack or plug at theterminal end, however, this is less preferred than on the POE end sincethere are many more types of jacks for receiving USB power. Therefore touse this arrangement for the USB connector would require a dedicatedpower adapter 2 dedicated to the specific USB receptacle on a particulartype of USB powered device.

As shown in FIG. 2, it is contemplated that the power adapter 2 of thepresent invention can be mounted in a standard AC electrical box 12. Thepower adapter 2 is shown mounted in a transverse configuration in astandard two (2) gang AC electrical box 12. This permits the use of thepower adapter 2 with a cover plate that fully encloses the power adapterand its wiring, such as the cover plate 14 shown in FIG. 3 which isfashioned to mount a USB powered device in the form of a tabletcomputer, such as an iPad® or the like, directly over the AC electricalbox 12. As set forth above, this is especially convenient for commercialand retail operations which have internal Wi-Fi and use tablet computersfor customer service or the like.

Notwithstanding, it is also contemplated that the power adapter 2 of thepresent invention be configured to be mounted, for example, within onegang of an AC electrical box 12 where the POE connector is notaccessible on the exterior of the AC electrical box 12, but one or moreUSB connectors are accessible on the exterior of the AC electrical box12. In such an embodiment, shown in FIG. 4, a cover plate, such as astandard cover plate with a rectangular opening or modular cover platehaving square openings for any of a variety of Ethernet jacks, telephonejacks, cable jacks, etc., can be used to mount an exposed USB connector6. This embodiment is well suited for use with charging stations inpublic facilities such as airports, conference facilities, restaurantsor cafés, etc., where the USB connector 6 of the power adapter 2 is madeavailable for public users to charge USB powered devices.

With specific reference to the embodiment having a power adapter 2 incombination with a cover plate for mounting a dedicated USB powereddevice, such as a tablet computer, as shown in FIG. 3, it is mostpreferred that the cover plate 14 include mounting elements and openingsfor ease of connection between the power adapter 2 and the device. Inthis regard, the mounting elements preferably include edge captureflanges 16 that extend over the edge of the dedicated device withoutsignificantly obstructing the screen, and cover locking security screws18, or other locking means, to prevent theft of the device.

The preferred dedicated cover plate also includes wire pass throughholes 20 positioned on the cover plate 14 for the USB wire to passthrough to the power adapter 2. Preferably, these wire pass throughholes 20 are distributed about the cover plate 14 to not only provideoptions for passing the USB wire through the cover plate 14, but also toaid in heat distribution on the back of the device. AC electrical boxmounting holes 22 are preferably positioned to secure the cover platedirectly to the AC electrical box 12, using treaded openings on the ACelectrical box itself. These AC electrical box mounting holes 22 arepreferably placed on the interior portion of the cover plate 14 so thatmounting screws passing through them are not accessible when the deviceis secured to the cover plate 14. Additionally, for more securemounting, stud mounting holes 24 are included to screw the cover plate14 directly into a wall stud, providing not only security from theft buta firm mounting of the device.

With respect to adapting the POE power to USB power, it is understoodthat any suitable transformer circuit can be used and that a variety ofalternatives will make themselves apparent to those skilled in theelectrical art. Notwithstanding, a preferred a transformer circuit isshown in FIG. 5.

As shown in the preferred circuit of FIG. 5, inductors L4 and L5 presentthe proper impedance to Ethernet data pairs 1+2, and 3+6 whileextracting the POE DC voltage at their center-tap connections. The POEDC voltage available at either the data or spare pairs of the networkdrop is rectified by D1 and D2. Filtering and HF suppression of the rawDC is provided by L2, L3, C1, C21, C20, Z1, L1, and C19, U2, T2, Q2 andassociated circuitry comprise the switching regulator circuitry thatconverts the POE DC voltage to an isolated, regulated 5 V DC supply.Isolated feedback for the regulator is provided by optoisolator Q1, D6and associated components U1, J1B and associated circuitry provides thephysical connection to the USB bus while presenting the appropriate USBdata line biasing to support USB devices, preferably including Appledevices, as well as a dedicated charging port mode.

Also part of this invention is the method for providing USB power to aremote location comprising the steps of running a POE cable from a powersource to a remote power adapter, transforming the POE power from thePOE cable to USB power, and making the USB power available to a USBpowered device. Using the preferred embodiment of the present inventiondescribed above, additional steps of mounting an AC electrical box atthe remote location, mounting the power adapter in the AC electrical boxand mounting a cover plate over the AC electrical box are contemplated.The method of the present invention also preferably includes plugging anEthernet plug on a POE cable with POE power into the POE connector ofthe power adapter.

Variations, modifications and alterations to the preferred embodiment ofthe present invention described above will make themselves apparent tothose skilled in the art. All such changes are intended to fall withinthe spirit and scope of the present invention, limited solely by theappended claims.

The invention claimed is:
 1. A power adapter for delivering electricalpower from a POE cable having power lines and data lines to a USBpowered device, the power adapter comprising a POE connector forreceiving electrical power from the power lines and data lines of thePOE cable, a transformer circuit, a USB connector, and a terminationpoint in the data lines of the POE cable prior to the data linesreaching the USB connector, leaving only the power lines of the POEcable to connect with and provide power to the USB powered device. 2.The power adapter of claim 1 wherein the POE connector is taken from thegroup consisting of an Ethernet receptacle, spring contacts, screw downcontacts, push-in contacts and stripped wires.
 3. The power adapter ofclaim 2 wherein the POE connector is an Ethernet receptacle.
 4. Thepower adapter of claim 1 wherein the USB connector is taken from thegroup consisting of USB Type A, USB Type B, USB Mini-A, USB Mini-B, USBMicro-A, USB Micro-B, Apple dock connector, spring contacts, screw downcontacts, push-in contacts and stripped wires.
 5. The power adapter ofclaim 4 wherein the USB connector is a USB Type A receptacle.
 6. Thepower adapter of claim 1 wherein one or more USB connectors areassociated with a single POE cable.
 7. The power adapter of claim 1wherein the power adapter is a self-contained device in a case.
 8. Thepower adapter of claim 1 further comprising a mounting element formounting the power adapter in an AC electrical box.
 9. The power adapterof claim 1 for mounting in an AC electrical box wherein the POEconnector is positioned to accept a POE cable internal to the ACelectrical box and the USB connector is positioned to be accessedexternal to the AC electrical box.
 10. The power adapter of claim 1wherein the termination point is within the transformer circuit.